compression question

[Trikeaholic]

On a 4 stroke, how should it "feel" when you do the compression "finger over the spark plug hole test"?? Should it blow your finger right off? I can keep it on and all I get is a fart noise. I dont know how to judge if it is high enough compression. Its the only thing I can come up with why the motor wont start, just wondering if I am right.

[Kilborg]

If the compression blows your thumb off the hole, the engine should at least run. From what you say, your pretty low on compression. Get a new bore and piston kit in there. The suzuki 230 (if thats what we are talking about) was notorious for developing some piston slap.

[jeswinehart]

i am sure it is gonna give you alot more then a small fart (lmao-sorry)
in fact,,, you should be very hard pressed to keep half yout thumb on it.

you probbly can rent a compression tester at a locale rental place. i would recomend to take one of your plugs along so you can match up the adapter that will probbly come with it.

john

[Trikeaholic]

thats what I thought, but it ran yesterday, and I used a used jug and piston. It ran great! must have killed it running it for 10 minutes, wierd.

[jeswinehart]

do that machine have a manual decompession release on it, up on top the head, probbly on the right side ? if so try dis-connecting it matt or lube it up real good.
i have dis-abled most of them i have had.

john

[Trikeaholic]

its not hooked up, and it has a spring that keeps it closed until you hook up the cable, I hate those things too. If you cant start a 200cc engine without a compression release, you shouldnt be riding!!

[350Xrider]

It should definately blow your finger out of the hole. The 230 Quadsports usually have poor cylinder to piston tollerances and wear out fairly quick and usually all of them smoke. But since you say it ran good the other day, I would have to say it is something else because there's not much of a chance that it wore out that quick if the spark plug and everything was right. Did it feel like it had lost any compression since the last rebuild?

[Trikeaholic]

since my top end was siezed, I got a used top end, and decided to try it. The stock piston and bore, it was really carboned up bad, and I just slapped it together with used parts, they looked like they had alot of hours on em. (trying to be cheap-I guess I learned my lesson!) I will get it down to the machine shop for a re bore tomorrow.